Re: [PATCH][V2] dvb_frontend: ensure that inital front end status initialized

From: Mauro Carvalho Chehab
Date: Thu Jul 20 2017 - 19:35:54 EST


Em Thu, 20 Jul 2017 23:12:07 +0100
Colin King <colin.king@xxxxxxxxxxxxx> escreveu:

> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> The fe_status variable s is not initialized meaning it can have any
> random garbage status. This could be problematic if fe->ops.tune is
> false as s is not updated by the call to fe->ops.tune() and a
> subsequent check on the change status will using a garbage value.
> Fix this by adding FE_NONE to the enum fe_status and initializing
> s to this.
>
> Detected by CoverityScan, CID#112887 ("Uninitialized scalar variable")
>
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
> drivers/media/dvb-core/dvb_frontend.c | 2 +-
> include/uapi/linux/dvb/frontend.h | 1 +
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
> index e3fff8f64d37..18cc3bbc699c 100644
> --- a/drivers/media/dvb-core/dvb_frontend.c
> +++ b/drivers/media/dvb-core/dvb_frontend.c
> @@ -631,7 +631,7 @@ static int dvb_frontend_thread(void *data)
> struct dvb_frontend *fe = data;
> struct dtv_frontend_properties *c = &fe->dtv_property_cache;
> struct dvb_frontend_private *fepriv = fe->frontend_priv;
> - enum fe_status s;
> + enum fe_status s = FE_NONE;
> enum dvbfe_algo algo;
> bool re_tune = false;
> bool semheld = false;
> diff --git a/include/uapi/linux/dvb/frontend.h b/include/uapi/linux/dvb/frontend.h
> index 00a20cd21ee2..afc3972b0879 100644
> --- a/include/uapi/linux/dvb/frontend.h
> +++ b/include/uapi/linux/dvb/frontend.h
> @@ -127,6 +127,7 @@ enum fe_sec_mini_cmd {
> * to reset DiSEqC, tone and parameters
> */
> enum fe_status {
> + FE_NONE = 0x00,
> FE_HAS_SIGNAL = 0x01,
> FE_HAS_CARRIER = 0x02,
> FE_HAS_VITERBI = 0x04,

If you're willing to touch the uAPI, please update its documentation:

$ git grep FE_HAS_SIGNAL Documentation/
Documentation/media/uapi/dvb/examples.rst: if (*stat & FE_HAS_SIGNAL)
Documentation/media/uapi/dvb/fe-read-status.rst: ``FE_HAS_SIGNAL``


Regards,
Mauro

Thanks,
Mauro